Analysis of the Switching Variability in Ni/HfO₂ -Based RRAM Devices

In this letter, we focus on the cycle-to-cycle variability of the low resistive state in Ni/HfO2-based resistive switching structures. The results show that several discrete current levels can individually last hundreds of cycles. They are a result of the random nature of the reversible conductive path formation through percolation processes, which could be attributed to a different shape, size, or number of conductive filaments. After successive cycles, the same or new filaments will nucleate in the weaker zones of the dielectric. In addition, the switching voltages related to the creation and dissolution of localized conductive paths are found to be statistically associated.